Résumé : This multicenter, open-label, uncontrolled study included 98 patients with mild-to-moderate hypertension and assessed the efficacy of pinacidil alone or in combination with hydrochlorothiazide (HCTZ) for 135 days. The initial dosage of pinacidil was 12.5 mg twice daily. The dosage was increased to 25 mg twice daily if diastolic blood pressure remained >90 mm Hg after 30 days. If blood pressure was still not controlled in 30 days, HCTZ 12.5 mg twice daily could be added. If target blood pressure was not reached after 30 days of combination therapy, the regimen was increased to pinacidil 25 mg twice daily plus HCTZ 12.5 mg twice daily. In addition, HCTZ could be added at any time if peripheral edema developed. Systolic and diastolic blood pressures decreased significantly after 30 days of treatment from 162.1 ± 14.1 mm Hg (mean ± SD) and 102.1 ± 5.0 mm Hg to 153.2 ± 14.9 mm Hg and 92.8 ± 9.0 mm Hg, respectively. Some additional benefit was observed during the following months of drug administration. Systolic and diastolic blood pressures were 140.5 ± 11.4 mm Hg and 84.3 ± 6.7 mm Hg, respectively, at the end of the study. At that time, 32 patients (32.7%) were receiving pinacidil only, 12.5 mg twice daily; 20 patients (20.4%) were receiving pinacidil 25 mg twice daily; and 46 patients (46.9%) were receiving pinacidil and HCTZ twice daily. HCTZ was added for incomplete blood pressure control in 15 patients (32.6%) and for peripheral edema in 31 patients (67.4%). The addition of HCTZ to pinacidil reduced the incidence of edema from 65.4% to 15.2%. The results of this study suggest that pinacidil was associated with a significant reduction in systolic and diastolic blood pressures in patients with mild-to-moderate hypertension. The high incidence of peripheral edema was largely reduced by the addition of HCTZ.